FOXBOROUGH — No offense to the Jacksonville Jaguars, but when any part of the Patriots is statistically comparable to the only 0-8 team, it’s probably a problem area.

So it is for the Patriots, who have reached the midpoint of the 16-game schedule with a 6-2 record, good for a two-game lead in the AFC East. They’ve won with a patchwork defense missing two injured captains, and with an inconsistent offense that’s also been impacted by injury, still waiting for their full arsenal of skill players to be available for the same game.

Injuries, more often than not, you can’t control. But the performance on the field is entirely under the team’s control, and in one key category, especially lately, the Patriots have struggled mightily. It’s factored into both of their defeats, and figures to be a hot-button story line the remainder of the season, starting with Sunday’s game against the Steelers.

Converting on third down. When it comes to the Patriots’ offense extending drives by turning a third-down play into a first down, the success rate this season has been surprisingly poor. Historically poor. Jaguars poor, which borders on embarrassingly poor.

How bad? The Patriots are 37 for 115 on third-down conversions, which is 32.2 percent. The only team in the AFC with a lower success rate is Jacksonville, at 29.5 percent. Among the 32 teams in the NFL, the Patriots rank 29th.

“It hasn’t been a strength for us, especially in the games we’ve lost,” quarterback Tom Brady said Wednesday. “It’s almost like we’re a good Canadian football team. But at the NFL, we’re just not doing anything on third down to stay on the field. That has to be something that over the next eight games, we have to do a lot better job of. We’re working at it, I’ll say that. It’s definitely a point of emphasis.”

It should be, based on New England’s recent showings on third down. In their past four games — road contests with the Bengals and Jets, home tilts with the Saints and Dolphins — the Patriots have gone a combined 9 for 49 on third-down plays, or 18.3 percent. They were 1 for 12 in losses to the Bengals and Jets, and are coming off a 2-for-10 effort last Sunday in a win over the Dolphins. In the last-minute victory over the Saints Oct. 13, the Patriots were 5 for 15.

The 32.2 percent clip isn’t what Patriots fans are accustomed to seeing. Since Brady became the starter in 2001, the team’s worst third-down percentage in any regular season was 2003, when the Patriots converted 37.0 percent (and went on to win the Super Bowl). Under Bill Belichick, the Patriots’ lowest regular-season conversion rate was 35.0 percent in 2000, his first season as head coach. Take those two seasons away, and from 2000-12, the Patriots have converted anywhere between 41.1 percent and 48.6 percent, the mark they had last year.

What’s changed to drop the number 16 percent? Lots, actually. Gone are possession pass-catchers Wes Welker, Danny Woodhead, and Aaron Hernandez. Shane Vereen, a versatile third-down running back, has been out since Week 1 with a broken wrist. Rob Gronkowski and Danny Amendola, two other possession receivers, have been limited to two and four games, respectively.

The Patriots are working with what they have. They just haven’t been very successful when the pressure down arrives.

“We’ve had opportunities and maybe not connected on them,” offensive coordinator Josh McDaniels said. “We’ve had a few breakdowns here and there in protection, whether that was blitz pickup or something along the front. There have been some plays where they had a good call against whatever we called and it really wasn’t a great match for that defense.

“I think that third down comes down to your ability to put people in good positions to succeed and then going out and executing at all of the levels.”

Not only have the Patriots had a hard time picking up first downs on third-down plays lately, they’ve found yards difficult to come by. Over the past two games, the Patriots have run 22 third-down plays (10 against the Dolphins, 12 against the Jets). They’ve had positive yardage on only five. Add up the yardage gained and lost on those 22 plays, and the Patriots have lost 1 yard.

Partly because of their lack of production on first down — the Patriots are gaining an average of 4.65 yards, which is 29th in the league — there’s been a wide range of yardage needed on third down. Against the Jets, the Patriots ran six third-down plays when they needed 10 yards or more. They converted none. The yardage needed was shorter against the Dolphins, with only two third-and-10 plays. Those weren’t successful, either. The Patriots also failed four times against Miami on third down when they needed 3 yards or less.

“I can’t speak for everybody, but for me being out there, I speak for myself, it’s lack of execution and lack of concentration,” said running back Brandon Bolden, who in the past four games has had the ball in his hands 12 times on third-down plays, gaining a first down just twice. “You see what you see, hit what you see, and live by that decision. Will it be the right decision every time? No, but you can work on trying to make it the right decision every time, and that’s what we’re working toward.”

Brady noted that it’s been emphasized at practice, but aside from a lack of consistent execution, it’s difficult to pinpoint one aspect of the Patriots’ third-down plays that isn’t working. Of the 49 third-down plays over the last four games, 11 were designed runs, with only three conversions. Brady was sacked nine times, scrambled once (getting the first down), and was 10-for-28 passing. Listening to the quarterback, it’s been one big group fail.

“I wish it was just pointing to one thing and saying, ‘This is the problem.’ But it’s been spread throughout every position and bad throws and bad reads and just missed assignments in general,” Brady said. “It’s not one thing, it’s a combination of things.”

Those things, more often than not the past month, have sent the offense to the sideline, and brought the punting or field goal unit on. Failure to convert a fourth-quarter third and goal at Cincinnati from the Bengals’ 1 could have cut into a 10-point deficit. Their inability to convert a pair of third-and-1 plays against the Jets was costly in a game the Patriots lost in overtime.

The going won’t be any easier Sunday against Pittsburgh’s fourth-ranked defense, but doing a better job of converting third downs will pay off for the offense. It’ll also assist the defense.

“It hasn’t been a strength for us, especially in the games we’ve lost,” Brady said. “To be a good offense you have to be on the field. We’re losing time of possession, which exposes your defense, it limits your ability to run the ball on offense because you feel like, ‘Oh, we have to throw it because we’re not going to get it on third down so if it’s second and long you have to throw it so you can get it on second down.’ It’s just, look, we have to make it happen on Sundays.”

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